Chapter 18 Integration of grafted Purkinje cell into the host cerebellar circuitry in Purkinje cell degeneration mutant mouse

Abstract

Publisher Summary This chapter aims at analyzing the progressive fate of grafted Purkinje cells (PCs), and their interactions with the host cerebellar cells. Despite time mismatch, embryonic PCs grafted into adult Purkinje cell degeneration (pcd) cerebellum migrate along stereotyped pathways to their final position in the deficient molecular layer, where they develop monoplanar dendritic trees composed of proximal thick branches and distal spiny branchlets, and receive appropriate synaptic contacts from adult host neurons. Despite the heterogeneous composition of the solid grafts, only neurons of the same category as those missing are able to leave the graft and to invade the host. The fact that the embryonic PCs can migrate, differentiate dendritic trees, and integrate synaptically into the deficient cerebellar circuitry, strongly suggests that signals for neurotropism, migration, neuronal differentiation and synaptogenesis are not limited to embryos, but can be expressed in the adult as well, at least in the pcd mouse cerebellum. The chapter concludes that embryonic neurons can induce a new type of plasticity in adult neural cells by generating a permissive microenvironment that could regulate gene expression of the adult neurons and glial cells.